What the hell is wrong with my car?

B6/7 S4/RS4
#10

It seems like after a longish highway drive, the car has a little more juice. The more I push it, the slower it gets.
Last time I logged it (a month ago), I was in the 6xx RPMs per second in warmer temps but after some long easy driving.

Back in February (colder temps), I had logged 800 RPMs per second. That said, back in February, I was neck and neck with saki’s RS4 as well just like 3 weeks ago (both times, easy highway driving before hand).

However, after a bunch of hard pulls with saki a month ago, my CEL came on because my fuel trims exceeded the acceptable range. It went beyond -10% adaptation (i.e. pulling too much fuel back).

My long term fuel trims are all on the rich side but obviously, I don’t race the car all the time so the only time I did get a CEL was when I did a lot of hard driving in a short period of time.

Of course, as the car gets hotter and hotter, the system will go richer and richer for safety purposes but I’m wondering if it’s going too far.

Then again, I’m no mechanic or tuner so I really have no idea. I’m pretty much confused at this point.

#11

Neck to Neck with a 12.7 Rs4 and today you ran 13.7. Seriously something to look at. From the sound of it. You said the car was running better on the way home. This to me would say that the blower and the car had some time to cool the oil temps down and to get the car out of what sounds like safe mode.

If you drove all that way and then let the car sit. You basically just let the car heat soak. When you go to the track its good to do a few back to back passes. This allows the car to get air past the oil coolers and obviously help cool the car down

Tell us more on this. What leads you to say this. Is there black smoke coming from the back of the car? Most supercharged apps are going to run MUCH more fuel then your standard NA cars.

#12

Unfortunately, back to back passes aren’t really an option. What would you recommend? Simply not shutting the car down while waiting to go back on? That very well might be a big chunk of today’s problem. The reality is that there’s going to be a wait before the next run. For the future, what is the recommended method?

When I punch it, there is smoke coming out the back. How much? Hard to tell as that’s all relative. Let’s just say there’s enough to see from my rearview mirror but not so much that would cause someone to say “holy crap, that’s a lot of smoke”. So a “mild” amount of black smoke? I’m also catless if that changes anything.

And as I mentioned above, my long term fuel trims are on the richer side and when I pushed the car hard for a while, I got a CEL for an adaptation number going beyond -10%.

Oh, and I did a quick pull against a JHM tune 4.2L manual converted A6 last week (evening, cooler temps) from about 50 kph to 130 kph and I was only slightly distancing myself from him. Both myself and the A6 driver were surprised. We both expected that I would leave him behind quite a bit.

#13

I’m not sure that back to back runs to “cool” the car down is optimal?? When I go to the track…to run a serious time that I care about…I arrive early before T&T starts (if your lucky and your gates open early) I park, open my hood, and throw a bag of ice on my IM with a towel wrapped around it so water doesn’t run down around the injectors and IM. I only have a 20 minute drive to the strip, but I still think cooling down is a serious factor. After about 30min I’ll go get a pass in to get my adrenaline down…lol Usually at our track if you get there early you can get passes in without sitting in the staging lanes for 10-15 min.

I would just wait until it cools down Axel, a lot of people stop going when it gets cooler too, which is even another positive. Good luck though, I hope you figure this crap out.

#14

73-77F temps is not going to cause my car to go from 12.5-12.7 to 13.7.

#15

This is exactly true. When I had my SRT-4 I ran 13.65 @ 103, in 85F temps.

My random thought of the day would lead me to ask how your MAF is looking.

#16

A few months ago it triggered some errors (sensor error). Every time I cleared it it came back 2 weeks later. However, it stopped coming back 6 weeks ago and hasn’t come back yet.
Not sure what to do about that one.

#17

I never said it would, but if you want to see good ass times your car being cool is pretty damn important. I think a heat soaked engine and horrible DA could cause a pretty shitty time. Saki just noted that he picked up almost 6 tenths because of shitty conditions. If you think something is wrong you should get JHM on the phone and do some logs, have them look into it from a technical standpoint instead of a thread full of “ifs” and “possible” causes.

#18

yeah, 12.75 @ 108.36 to 13.33 @ 105.5 was the good weather/shit weather gap for me…however I also had 91 octane in the second time.

That’s pretty huge. 6 tenths and 3 MPH.

Now, axel’s car in my mind should have run the following

last fall, great DA, no tune, catless 2.25" exhaust + a couple of LW parts = 13.8 @ 101 (basically stock time…going catless with no tune isn’t good for much)
it ran 14.1 @ 98-99 so was off a few tenths and a couple of MPH. His launches weren’t great so that’s part of it. Still a bit slow but not drastically.

this week, shit DA, JHM supercharged and lots of bolt ons = 12.80 @ 110

this fall, great DA, same mods = 12.40 @ 113-114

Just my guesses of course on what a car with those modlists should run in those conditions on our track. I think next Detroit meet when jaybquick and count vohn are there, he should bring the car down for them to check out with their own eyes.

AXEL - post your timeslip up so we can get a look at the various times etc. and so I can see exactly when you ran to determine DA.

#19

I think the heat soak played a large part as Carlos mentioned. Will have to go back on a cooler and more importantly, less busy evening. The 14.1 were really crappy launched and not a good indication. I think a 13.9 would have been easily achievable with better traction at launch. Still, I was surprised at the bad times.
I still think there’s some other smaller issues but not completely sure.
I’ll post the timeslip when I get home later.

As for the JHM guys in Detroit, I’ll be there for sure. Is that usually in the fall?
JHM has my next tune available with LA so we’ll see how that works out once I get it.

#20

I’m trying to explain that the 14.1 even if you launched it terrible still had a trap speed that was around 98 MPH. Your trap speed isn’t going to change 4 MPH becuase of a poor launch. The distance of the track and your accelerating power will determine your trap speed, not how well you launch the car (well…it won’t move the needle 4 mph or something on these cars). Provided you shifted gears reasonably well, the trap speed will be within 1.0 MPH of itself 95% of the time for the same car at these power levels.

Look at my runs from April…I made like 13 passes, including 8 where I wasn’t taking it easy or screwing up gear changes. The variance in trap speed was tiny on these runs. Only one of those was more than 1% off the best of the day…and that was 1.7% off.
12.75 @ 108.3, 1.83 60’
12.77 @ 108.2, 1.85 60’
12.79 @ 108.2, 1.85 60’
12.81 @ 107.7, 1.84 60’
12.82 @ 108.0, 1.83 60’ (vs. the C63 AMG 13.7 @ 110.6)
12.90 @ 107.2, 1.88 60’ (vs. B8 S4 GIAC 91 TUNE…he ran 12.92 @ 109.
12.90 @ 107.4, 1.86 60’
12.97 @ 106.4, 1.87 60’

#21

Saki’s right about the correlation to trap speed; you are losing some good power. The rich symptoms under load sound like a small boost leak. Losing any of that metered air will make for a rich condition. What is the baseline psi for that kit anyway? A leak at lower pressures is generally easier to find.

edit: what I meant by the last statement was that if you have a leak at lower boost pressures it is generally easier to find than leaks only found at higher pressures. Pressure testers are cheap and effective.

#22

Great…sigh…

Here’s the timeslip.

http://www.gauntlet.net/audi/13-7-quarter-mile.jpg

#23

Ok, just spoke to JHM’s tuner for the last hour and he fully confirmed it was simply heat soak.
Looks like I’ll need to go back on a less busy evening and bring some ice with me.

Phew.

#24

glad you got some confirmation. That doesn’t require $$ :slight_smile:

#25

Staging lane heat and heat soak will kill the potential of a good run. Not to mention the DA Close to 2500. The Issue that your looking at is the performance of this and any real kit is going to be on the road where your getting REAL air across the car.

Here is another great example. A strong running 11second car. Is the RS4 APR car I worked on. We went through 30lbs of Ice to keep the temps in check. In order to keep the heat at bay.

http://audirevolution.net/addons/albums/images/301210427.jpg

You don’t need this ice if your driving the car as there is air flowing across the car keeping it cool. If you’re going to park the car and want to dyno or track the car you’re going to need to make sure to keep the heat in check.

There is a small list of things that go with that. You can attribute the lower trap times from the heat for sure. As the tune in the car will limit the power when oil and coolant temps exceed a limit.

More so then that I believe its the lower shifting RPM. Axel spoke on shifting at the 6000rpm range rather then 7200. The car just never got a chance to get its legs.

Due to the limited power that these motors can handle if your looking to get a solid time performance wise from the Supercharger your going to need to get out of the hole strong and let the RPM ride out the rest of the way. To keep the motors alive the Tune for the supercharged cars is quite tame and pulls power each gear. closeing the Throttle by over 45% after 5800. The car will still continue to make more and more power. Even with the closed throttle, the 11sec passes of jay and D are on tunes that limit the power more each gear and each RPM. So you need every bit of RPM and a great start.

#26

Count, what do you think about using water/meth injection to lower the intake temps down during runs? Of course the ice would probably still be the best idea to cool down the engine after driving to the track but would the water/meth injection be worth using at all for during runs?

I ask because Dan at RAI kept pimping their water/meth injection kits at the last local meet. He has a B6 S4 with a MP90 that they built for a customer and then he later purchased from them. He said the meth helped lower the intake temps down a bunch on that car. Now I know it is not the same blower setup but I just wanted to get your thoughts on this for the JHM blower. There is a longer back story about why they went with MP90 instead of the TVS but I want to stay on point.

[quote=“CountVohn,post:25,topic:3646”]
I will keep this in mind for when I take my car back to the strip. Thank you!

#27

That car is a tip right Jimmy? It ran 12.59 @ 112

Audirevolution.net/quartermile

#28

I have never actually seen the car in person but it appears that car is the only one listed with a RAI M90 S/C.

#29

I bet water meth would help, I like the idea of it as a helper not something the car relies on the make power (race gas tune on pump+w/m for instance)